Long strings of numbers instead of contacts

Fellow forum members, is someone here well-versed in Androids? Yesterday, my phone randomly decided to change my contact name and number into a long string of numbers, all on itself. I have Samsung S7 and I do not remember using any suspicious app to make it happen. Also, my group messages are failing. The long number string also applies to my other contacts. What to do?

For all I knew, Google always do an automatic contact back-up so log it out and in shall do the job… voilà!

May be there is a bug of your software,
try to restart your phone and check
Restore your contacts using your email accounts.

Please check the link below